What are "server_version_split" and "number_of_event_types" in "FormatDescriptionEvent" class?

[ghost]

code reference:

https://github.com/julien-duponchelle/python-mysql-replication/blob/ea61cca85fd1f526f393829ee5eb50dda42ff86e/pymysqlreplication/event.py#L397 https://github.com/julien-duponchelle/python-mysql-replication/blob/ea61cca85fd1f526f393829ee5eb50dda42ff86e/pymysqlreplication/event.py#L398

There are two attributes, "server_version_split" and "number_of_event_types", and i have not find those two fields in MySQL documents (I saw https://dev.mysql.com/doc/dev/mysql-server/8.0.40/page_protocol_replication_binlog_event.html).

So what are they? Maybe they are in some older MySQL version?

Thanks.